<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>01_JS的三种引入方式</title>
</head>
<body>
    <button onclick="alert('请先登录!')">点击即玩</button>
    <button onclick="console.log('点我干哈!')">点击即玩</button>
    <h1 id="aaa"></h1>
    <script>
        console.log('我是JS代码块');
        console.log(aaa);
    </script>
    <script src="01.js"></script>
</body>
</html>